You could have faced a strange issue when accessing SharePoint 2010 list forms on anonymous access. I have a Publishing Site with FBA authentication. I was using calendar control with overlays to display the events to all users. calendar control uses "DispForm.aspx" to display the event details to the user. But when anonymous users click on the Title, the page redirects to the Login form.
Its the problem with ViewFormPagesLockdown.
To overcome this problem, I executed the below code in PowerShell;
To determine if a site has ViewFormPagesLockdown enabled run the following:
get-spfeature -site http://sitecollectionURL
If ViewFormPagesLockDown is listed, it's enabled.
$lockdown = get-spfeature viewformpageslockdown
disable-spfeature $lockdown -url http://sitecollectionURL
If anonymous is already setup, you may need to disable\re-enable anonymous on the site.
Happy Coding :)